I tried this before.
1) Take a friend with you in the instance this is a must
2) Tell him that you need the item IF it drops + tell him to support you making the
other guy that needs it 2 to just pass it.
So if the item drops your friend can support you if someone else
needs it 2.. you have to start begging like: pls dude i came here for this item or
i did this instance a hundred of times and it didn't drop nd crap like that :P
your friend has to do the same.
i Did this to a hunter in BM with the trinket that second boss drops and whats the funny think i was a protection warrior...and i got the trinket that the hunter came for...=p
thats all.